Coronary endothelial dysfunction after heart transplantation predicts allograft vasculopathy and cardiac death.

BACKGROUND: Coronary endothelial dysfunction may be an early marker for cardiac allograft vasculopathy (CAV) in orthotopic heart transplant recipients. Using serial studies with intravascular ultrasound and Doppler flow-wire measurements, we have previously demonstrated that annual decrements in coronary endothelial function are associated with progressive intimal thickening. The present study tested whether endothelial dysfunction predicts subsequent clinical events, including cardiac death and CAV development. METHODS AND RESULTS: Seventy-three patients were studied yearly beginning at transplantation until a prespecified end point was reached. End points were angiographic evidence of CAV (>50% stenosis) or cardiac death (graft failure or sudden death). At each study, coronary endothelial function was measured with intracoronary infusions of adenosine (32-microgram bolus), acetylcholine (54 microgram over 2 minutes), and nitroglycerin (200 microgram) into the left anterior descending coronary artery; intravascular ultrasound images and Doppler velocities were recorded simultaneously. Of the 73 patients studied, 14 reached an end point during the study (6 CAV and 8 deaths, including 4 with known CAV, 1 graft failure, and 3 sudden). On the last study performed, the group with an end point had decreased epicardial (constriction of 11.1+/-2.9% versus dilation of 1.7+/-2.2%, P=0.01) and microvascular (flow increase of 75+/-20% versus 149+/-16%, P=0.03) endothelium-dependent responses to acetylcholine compared with the patients who did not reach an end point. Responses to adenosine and nitroglycerin did not differ significantly. CONCLUSIONS: Endothelial dysfunction, as detected by abnormal responses to acetylcholine, preceded the development of clinical end points. These data implicate endothelial dysfunction in the development of clinically significant vasculopathy and suggest that serial studies of endothelial function have clinical utility.

Assessing coronary blood flow dynamics with the TIMI frame count method: comparison with simultaneous intracoronary Doppler and ultrasound.

This study compared the TIMI frame count (TFC), which has been proposed as a method for quantifying coronary blood flow, with coronary flow and microvascular function measured with intracoronary Doppler and intracoronary ultrasound. Coronary blood flow volume was calculated from coronary blood velocity (by intracoronary Doppler) and lumen area (by intracoronary ultrasound) in the LAD in 46 post-heart transplant patients at baseline and after intracoronary adenosine. TFC correlated significantly with average peak coronary blood velocity (r = -0.42; P = 0.004) and coronary lumen area (r = 0.39; P = 0.008), but not with coronary blood flow volume (r = -0.01; P = 0.96) or the coronary flow reserve response to adenosine (r = 0.09; P = 0.58). In conclusion, TFC is a simple method of assessing coronary blood velocity but not volumetric flow. While TFC does not predict coronary flow reserve, as a measure of velocity it does provide an assessment of basal microvascular tone, information that is complementary to that afforded by flow reserve measurements.

The use of antiplatelet agents in acute cardiac care.

Antiplatelet therapy with aspirin has long been established as standard therapy in the management of conditions such as ST-elevation myocardial infarction and the acute coronary syndromes (unstable angina and non-ST-elevation myocardial infarction). Recently, several more potent platelet inhibitors have been developed and tested in randomized clinical trials. This article reviews the current state of the art of antiplatelet therapy.

Antithrombotic and thrombolytic therapy in acute cardiac care.

This article explores the use of antithrombotic and thrombolytic therapy in acute cardiac care, and looks at traditional anticoagulant agents, newer antithrombin agents, thrombolytic agents, and others.

Probable Kawasaki disease in a 52-year-old man presenting with acute myocardial infarction treated with percutaneous revascularization.

This is a case report of a 52-year-old man who presented with an acute myocardial infarction. In the process of performing an angiogram to delineate the anatomy for possible percutaneous transluminal coronary angioplasty, large, diffuse coronary aneurysms were observed. When the vessel was opened, several aneurysms were seen to contain thrombus. The size, location, and diffuseness of the aneurysms are suggestive of Kawasaki disease.

Validated risk stratification model accurately predicts low risk in patients with unstable angina.

BACKGROUND: In the mid 1990s, two unstable angina risk prediction models were proposed but neither has been validated on separate population or compared. OBJECTIVES: The purpose of this study was to compare patient outcome among high, medium and low risk unstable angina patients defined by the Agency for Health Care Policy and Research (AHCPR) guideline to similar risk groups defined by a validated model from our institution (RUSH). METHODS: Four hundred sixteen patients consecutively admitted to the hospital with unstable angina between January 1, 1995, and December 31, 1997, were prospectively evaluated for risk factors. The presence of major adverse events such as myocardial infarction (MI), death and heart failure was assessed for each patient by chart review. RESULTS: The composite end point of heart failure, MI or death occurred in 3% and 5% of the RUSH and AHCPR low risk categories, respectively, and in 8% and 10% of AHCPR and RUSH high risk categories, respectively. Recurrent ischemic events were best predicted by the RUSH model (high: 24% vs. medium: 12% and low: 10%, p = 0.029), but not by the AHCPR model (high: 14% vs. medium: 13% and low: 9%, p = 0.876). The RUSH model identified five times more low risk patients than the AHCPR model. CONCLUSIONS: Both models identify patients with low and high event rates of MI, death or heart failure. However, the RUSH model allowed for five times more patients to be candidates for outpatient evaluation (low risk) with a similar observed event rate to the AHCPR model; also, the RUSH model more successfully predicted ischemic complications. We conclude that the RUSH model can be used clinically to identify patients for early noninvasive evaluation, thereby improving cost effectiveness of care.

An unusual mechanism of coronary stent dislodgment and localization.

Stent dislodgment from its delivery catheter is a rare yet clinically important entity in cardiac catheterization. We report a highly unusual case of stent loss and subsequent localization in the guiding catheter. Our hypothesized mechanism of stent dislodgment should be recognized by the medical community.

A simplified lesion classification for predicting success and complications of coronary angioplasty. Registry Committee of the Society for Cardiac Angiography and Intervention.

In 1988, the American College of Cardiology/American Heart Association (ACC/AHA) Task Force on Assessment of Diagnostic and Therapeutic Cardiovascular Procedures presented a classification of coronary lesions utilizing 26 lesion features to predict the success and complications of balloon angioplasty. Using data from the Registry of the Society for Cardiac Angiography and Interventions (SCAI) we evaluated the ability of this classification to predict success and complications. Lesion success, death in hospital, emergency cardiac bypass surgery, and major adverse events were evaluated in 41,071 patients who underwent single-vessel angioplasty from January 1993 to June 1996. Logistic models using the ACC/AHA lesion classification, vessel patency, or both, were compared. A new classification based on the interaction of the ACC/AHA classification plus lesion patency was compared with the existing ACC/AHA classification. Vessel patency, added to the ACC/AHA classification, improved prediction of lesion success (p

The relative influence of lesion length and other stenosis morphologies on procedural success of coronary intervention.

As coronary interventional technology improves, the influence of lesion length (LL) on procedural success and device selection may vary. Thus, the authors prospectively analyzed 957 consecutive coronary interventions (CI) in 1,404 stenoses to ascertain the influence of lesion length on CI outcome. Stenosis morphology was prospectively classified by the AHA/ACC criteria. LL was analyzed both as dichotomous (S: < 10 mm, L: > 10 mm) variables and by the three-tiered AHA/ACC criteria (I: < 10 mm, II: 10-20 mm, III: > 20 mm). There was a significant univariate relationship between CI success and S stenosis (S: 95.8% vs L: 91.8%, p = 0.002 and I: 96.0%, II: 91.7%, III: 89.3%). Numerous interrelationships involving the morphologic characteristics were noted: lesion morphologies associated with S lesions were concentric (p = 0.0001) and had smooth contour (p = 0.0001), ostial location (p = 0.05) and little calcification (p = 0.0007), while irregular contour (p=0.0001), calcification (p=0.0076), eccentric (p=0.0001), thrombus (p = 0.0001), recent (p = 0.0001) or chronic (p = 0.001) total occlusion were associated with L lesions. When these relationships were taken into account by multiple logistic regression analysis, lesion length was not predictive of procedural outcome (p = 0.099). One morphologic type was associated with increased CI success: irregular contour (p = 0.022); recent (p < 0.0001) or chronic (< 0.0001) occlusions were associated with decreased CI success. Another factor considered was device selection: S lesions were associated with greater balloon angioplasty usage (p = 0.002), whereas more coronary stents (p = 0.024) and rotoblator (p = 0.018) devices were used in L lesions. More balloon angioplasty was performed in concentric (p < 0.0001) lesions; interventional devices were employed more often in eccentric (p < 0.0001) and irregular lesions (p < 0.0001). More complications were noted in lesions with thrombus (p = 0.0002), but lesion length was not predictive (p = NS). Lesion length is not a significant predictor of procedural success when adjusted for other lesion morphologies in the modern interventional era. The availability of new devices has improved the results in longer lesions since the AHA/ACC criteria were originally proposed.

Clinical practice guidelines in unstable angina improve clinical outcomes by assuring early intensive medical treatment.

OBJECTIVES: To determine the influence of clinical practice guidelines on treatment patterns and clinical outcomes in unstable angina and the effectiveness of guideline reminders on implementing practice guidelines, two groups of medium and high risk patients with unstable angina were compared. BACKGROUND: New guidelines have been published by the Agency for Health Care Policy and Research (AHCPR) for evaluating and managing patients with unstable angina. The impact of these guidelines to improve the quality of care has never been tested. METHODS: Group 1 included 338 consecutive medium or high risk patients admitted before publication of the AHCPR guidelines, and group 2 consisted of 181 consecutive similar risk patients admitted after institution of the AHCPR guideline reminders at this institution. Dissemination of clinical practice guidelines was ensured by a grand rounds lecture and by posting guideline reminders on all group 2 patients' charts within 24 h of admission. RESULTS: The two groups were similar in terms of most baseline characteristics, including hypercholesterolemia, diabetes, hypertension, smoking history, baseline ST segment depression and previous coronary artery bypass graft surgery. Group 1 patients were older (68+/-13 vs. 63+/-16 years, p = 0.001) and more frequently had a previous myocardial infarction (39% vs. 22%, p = 0.001). Group 2 patients more frequently required intravenous nitroglycerin to control the index episode of chest pain (43% vs. 34%, p = 0.003). Group 2 patients more frequently received aspirin (96% vs. 88%, p = 0.009) during admission and underwent coronary angiography (71% vs. 58%, p = 0.006). More importantly, group 2 patients received oral beta-blockers (p = 0.008), aspirin and coronary angiography (p = 0.001) earlier than group 1 patients and experienced recurrent angina (29% vs. 54%) and myocardial infarction or death less frequently (3% vs. 9%, p = 0.028). CONCLUSIONS: In unstable angina, clinical practice guidelines were associated with greater use of aspirin and coronary angiography and greater use and earlier administration of beta-blockers. Variation in drug use over time was also reduced. Objective improvement in clinical outcome was also noted. Thus, practice guidelines improve the quality of care of patients with unstable angina.